The present invention relates to a rotational projectile having a hollow metallic nose portion which contains a charge adapted to detonate by impact against a target without the use of any fuse.
When such a projectile is launched from a weapon, for instance a gun or cannon, it is of importance that a complete conversion of the charge or charges does not take place in case the projectile inadvertently hits an item relatively near the weapon. A conversion near the weapon of course involves a great danger of damaging the weapon and injuring the operator or operators of the weapon.
It is known to secure projectiles against complete conversion near the weapon by use of mechanical means inside the projectile. Such mechanical means have, however, and in particular for small caliber projectiles, been found to increase the costs to an unacceptable extent. The object of the present invention is to achieve a projectile which without the use of mechanical means is secured against complete conversion by impact near the weapon.
The above object is achieved with a projectile as defined in the succeeding claims.
The invention is based upon the utilization of centrifugal forces caused by the rotation of the projectile in order to cause a forwardly directed force which tends to displace the component situated in the insert forwardly.
In order to explain the invention it is considered necessary to make a review of the accelerations, retardations and inertia forces occurring during the launching of a projectile from a weapon.
The linear accelerations during launching of projectiles for which the invention is most likely to be used lies in the range of 20,000 to 120,000 G, and gives rise to large forces which tend to displace charges or components of charges rearwardly inside the projectile as long as the thrust from the propellant charge acts on the projectile in the gun barrel.
When the projectile leaves the weapon it will be retarded in its path because of the air resistance, and the retardation may be in the order of 50 G.
Those parts of charges or components of charges that are situated in a relatively large radial distance from the longitudinal axis of the projectile will, due to the rotation of the projectile, be exposed to centrifugal forces which are equivalent to accelerations being substantially larger than the retardation. The centripetal accelerations may for instance be in the order of 1,000 G.